TMR, no it doesn't because the DT990's bass is very quick (thanks to open design), so it doesn't bleed into the rest of the sound like typical closed cans with boomy bass. It works so well, its my favorite bass of all headphones I've used.

Yeah I thought as much. I'd probably eventually want to use mine to replace the AD700 as gaming headset, but I don't quite want to velcro the labtec boom mic onto it just yet. Would ps3 -> mixamp -> tubeamp -> DT990 work? I guess I'd have to further amp the headphone while the mic only uses mixamp.

I haven't tried it, but I can't imagine +25dB working out too well. I haven't tried it, and I sure wouldn't want to risk my drivers on it if I owned a pair. Drivers like that just don't do really low bass They don't have the excursion. Even my HD650s start making rather alarming noises if you try and put too much bass through them. +25dB added to the bass and played through an amp strong enough not to clip at a normal listening volume is liable to break a lot of bass-lite headphones.

They aren't all LCD-2s which will take 15 whole watts and play at 133dB with less <1% THD.

5hz at what would be stupidly high SPL if it wasn't subsonic doesn't even faze my XB700s. You can't hear a thing, but you can feel them. That means its doing it properly and you're not just hearing higher order harmonics.

It only took about +12db from iTunes eq for me to be able to hear pretty well lower frequencies on the AD700. I can't comment for the lowest amount of extension down to 20hz and below, but it was enough to make pretty much every form of music enjoyable. You literally go from not being able to hear some of the reverb in extended low tones and bass drums to being able to hear them-- even feeling them a little bit. Nothing like some other headphones.

It only took about +12db from iTunes eq for me to be able to hear pretty well lower frequencies on the AD700. I can't comment for the lowest amount of extension down to 20hz and below, but it was enough to make pretty much every form of music enjoyable. You literally go from not being able to hear some of the reverb in extended low tones and bass drums to being able to hear them-- even feeling them a little bit. Nothing like some other headphones.

At what like 60hz or something? That's usually what the lowest band on a standard 10 band graphic EQ is and that's not low at all. That's about where bass starts for me

32hz. Even without an EQ you can hear bass down to 40hz with the AD700 using an individual tone generator, but it's very low.

It certainly has the aptitude to produce lower tones, it's just not competent at it.

That actually is fairly low. The AD700s are only down 10dB there so EQ still might do some good. That's fairly close to the SA5000s I owned briefly. I was running my D2+ to my Bithead and turned the Mach3Bass up to the maximum and they were still to thin with bass heavy electronica. They were great if you were listening to something with nothing deeper than semi-modern tuned-to be-audible-over-crappy-speakers high pitched kick drum.